Use of Morphological Method to Investigate the Influence of Surface Texture on Dimensional Measurement of Additively Manufactured Parts

The high level of surface roughness of additively manufactured (AM) parts post challenges to the applicability of different dimensional measurement techniques, including tactile, optical and XCT. Tactile measurement is traditionally considered to have the best accuracy and traceability. However, tactile measurement can be significantly affected by the mechanical filtering effect. This work sets out to investigate the influence of the mechanical filtering effect of tactile measurement on AM parts. Both experiential and simulation work are unitised to reveal this effect. Particularly the numerical simulation based on the morphological method allows the single influence factor, i.e., the tip diameter to be investigated. The maximum measurement errors caused by the stylus tip mechanical effect are determined by the convex hull points of the measurement profile, which is equivalent to using an infinitely large stylus tip. The CMM and XCT results of measuring the AM cylinder diameters are compared, along with the application of morphological method to “compensate” the mechanical filtering effect of the stylus tip.